Grouped contacts sync

Hi,
I just upgrade my Xperia SP to Cyanogen 12.1 (Android 5.1) and setup a fresh davdroid sync with my owncloud 8.1 server.
When I try to sync my contacts, I can see all of them for a few seconds in the contacts app, then those in a group disappear. I can’t display them even if I modify the display settings (view all contacts or set a custom view). So I only have the non-grouped people.